Componentize component_updater: Split crx_file code off into its own component.

extensions/common/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
 
 # GYP version: extensions/extensions.gyp:extensions_common
 source_set("common") {
   sources = [
     "api/messaging/message.h",
     "api/sockets/sockets_manifest_data.cc",
     "api/sockets/sockets_manifest_data.h",
     "api/sockets/sockets_manifest_handler.cc",
     "api/sockets/sockets_manifest_handler.h",
     "api/sockets/sockets_manifest_permission.cc",
     "api/sockets/sockets_manifest_permission.h",
     "common_manifest_handlers.cc",
     "common_manifest_handlers.h",
     "constants.cc",
     "constants.h",
-    "crx_file.cc",
-    "crx_file.h",
     "csp_validator.cc",
     "csp_validator.h",
     "dom_action_types.h",
     "draggable_region.cc",
     "draggable_region.h",
     "error_utils.cc",
     "error_utils.h",
     "event_filter.cc",
     "event_filter.h",
     "event_filtering_info.cc",
@@ skipping 197 matching lines @@
       "manifest_handlers/nacl_modules_handler.h",
     ]
   }
 
   if (is_win) {
     cflags = [
       "/wd4267", # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     ]
   }
 }